 function Map(ele){
     //1.保存下地图对象
           this.ele=ele
     //2.记录 地图的相关属性
           this.width='800px'
           this.height='400px'
 }
 Map.prototype.create=function(){
      this.ele.style.width=this.width
      this.ele.style.height=this.height
      this.ele.style.background='url(./bg.png)'    
      this.ele.style.border='10px solid green'    
            
 }